A $1.4 billion expansion of Stemmons Freeway between Interstate 635 and Denton was completed in 2017. The project was phase 1 of the planned ultimate corridor design. The new collector-distributor lanes between the Bush Turnpike (SH 190) and Rayburn Turnpike (SH 121) are hugely beneficial, but other parts of the project were built to low standards with narrow lanes. Future phases of the corridor expansion are not scheduled as of 2018.